This invention relates to transferring information or data from a data transmitter including a controllable light source, such as a computer having a cathode ray tube (CRT) screen display to a portable information device (e.g., a wrist instrument such as a multifunction electronic wristwatch).
The use of both computers and hand-sized, portable information devices continues to expand. Various methods have been developed for transferring information between computer processors (e.g., both synchronous and asynchronous serial communication devices), using communications interface conventions such as RS232C, RS449A and V.35. The binary coded signals may be transmitted in standard codes such as ASCII, EBCDIC, with established protocols providing for handshake procedures, starting, stopping and checking the data transmitted. Many transfer methods require a direct, electrical connection between devices. Such direct interconnections can be cumbersome, and in some circumstances impractical, due to the additional hardware requirements involved. Other communication methods utilize radio-frequency (RF) technologies or optical technologies to perform information transfer. RF technology is deficient because it also requires additional hardware, as well as increased power requirements for the transmission of information.
There are several ways to use optical technology for transferring information. One well-known method utilizes a light pen to detect and select information on a CRT. This method requires that the user manually move the light pen to each object on the screen to read an entire image. This method of data capture is inherently slow and can be prone to user errors (e.g., skipped objects). Possible interference from other signals requires placement in close proximity to the desired signal. Another drawback of light pen methodology is the necessity for peripheral hardware in addition to the portable device or incorporated into the portable device specifically for information transfer back to the device controlling the CRT.
An alternative implementation of optical technology utilizes a combination of optical emitters and photosensors to transfer information. Typically, hardware is dedicated specifically to both devices of the transfer process to insure that the receiver and transmitter are set to operate at the same transmission rate or baud rate. The device to be loaded with information is placed in front of the emitters and the information transfer is started. Unfortunately, this method of information transfer also requires specialized hardware and is often not compatible with existing hardware installations. Various proposals have been made for supplying binary coded data simultaneously with television broadcast signals at special small window locations on the CRT screen. Such proposals, discussed in exemplary U.S. Pat. No. 4,999,617 issued Mar. 12, 1991 to Uemura et al; and U.S. Pat. No. 3,993,861 issued Nov. 23, 1976 to Baer require photosensor devices touching or closely focused at a data image on the CRT screen, and sometimes held with vacuum cups.
As the use of portable information devices expands, there is an increasing need for such devices to be flexible in their functionality. Many existing portable devices have been designed for multiple functions, such as a combination watch/calculator. Wrist instruments have expanded from their time keeping role to include: databanking, chronometer, alarm, computation, odometer, paging, and communication functions. A disadvantage of many existing portable information devices is that they cannot easily be downloaded with programs providing new functionality. A further disadvantage of many existing portable information devices is that their databases cannot be easily updated without manually entering new data. The existing devices that can be updated typically have very limited input capabilities because they either have no keyboards at all or very rudimentary keyboards, or else they require that the updating occur from specific hardware. This severely limits the user's flexibility because the user must have easy access to updating hardware, which will most likely not be portable. Wristwatches in particular are difficult for entry of information or updating information. Various schemes have been proposed for entry of data using pushbuttons or tiny keyboards, none of which have been entirely satisfactory. An optimum configuration would be one where the portable device could be updated from any controllable light source such as a CRT video display screen found in desk size computer monitors and television sets.
It would therefore be desirable to provide a portable information device with which downloading of information can be performed without physically connecting or requiring close proximity of the portable device to the information source. It would also be desirable to provide a portable information device with which simpler data transfer or downloading of information can be performed without the use of additional peripheral hardware on the sending computer system or other light sources. It would further be desirable to provide a portable information device that suitably receives asynchronous serial data at the highest baud rate of which it is capable of receiving reliably from the source device. It would be even more desirable to provide a portable information device which can be downloaded from controllable light sources such as existing CRT video displays without requiring any hardware modifications.